The present invention relates to a pressure seal apparatus installed at the fiber products take out and feed in openings of a high pressure steamer vessel body.
Heretofore, for this kind of pressure seal apparatus, the device installed at the fiber product feed in the opening side of a high pressure steamer vessel body is almost the same as that installed at the take out opening side. Its structure ordinarily included a pressure seal apparatus as used for shielding the inside of a vessel body from external air by means of a roll seal mechanism. The roll seal mechanism consists of a seal block installed at the fiber product feed in opening or at the take out opening, and includes left and right seal rolls rotating in contact with each other to form a nip plane when the fiber product is fed in or taken out, and a sealing member (for example intermediate rolls) intervening between the above mentioned seal rolls and the seal block.
However, one of the problems in such a pressure seal apparatus is that the pressure contact or close contact point between the above-mentioned sealing member and the pair of left and right seal rolls is positioned forming almost a right angle with the nip plane provided by the seal rolls against their axial center, therefore, it experiences large internal pressure over a wide area corresponding to 1/4 of the circumferential plane of the seal roll. Accordingly, it is necessary to have the above-mentioned seal rolls bear a large pressure load for preventing pressure seal leakage from the nip plane at the seal rolls, and leaving a fear of damaging fiber product passing through the nip plane.
Another problem when maintenance is done on a pressure seal apparatus as internal vessel pressure is directly borne by the seal apparatus, maintenance work can not be done unless the inside vessel pressure is returned to normal atmospheric pressure. Further, when there is something wrong in the pressure seal apparatus there is a fear of causing pressure leakage, such as blowing out high pressure vapour from vessel inside, which may cause a very dangerous condition for workers around the vessel, thus generating a serious safety problem, but no apparatus has yet been proposed for solving the problem.
In addition to these various problems, in a roll seal mechanism provided in conventional pressure seal apparatus, to afford a sure pressure seal by giving a prescribed pressing force over the nip plane formed by contact of the left and right rolls and the pressure contact plane between the seal rolls and the intermediate rolls, a seal block retaining the intermediate rolls in a rotatable manner is provided at fiber product take out and feed in openings so that the pressing force in a pressure contacting direction of the intermediate rolls onto the seal rolls is regulated by a hydraulic mechanism, but there is a shortcoming with such a very complicated structure.